Frequently Asked Questions about Maize
We get asked a lot of questions about Maize throughout the year, so we’ve compiled this FAQ to help you find the answers you need quickly! You can also read our in-depth Ultimate Guide to Forage Maize for more answers and tips.
When should maize be sown?
Maize is typically sown from mid-April, or as soon as conditions allow. The soil needs to be at a consistent 8° before drilling should commence. Normally, drilling should have been completed by the end of May to allow for a harvest in good time. Growing under plastic, the drilling time can be brought forward, as the soil only needs to get to 6° consistently. With recent weather patterns hindering operations, it is useful to remember that a late sown crop into warm soil and good conditions, is often not far behind an early sown crop into cold soils.
What rate should maize be sown at?
A standard rate of 110,000 seeds per ha is often used, but this can be adapted to suit the individual conditions or variety choice. Sowing rates should be decreased it is a later sowing as the wider spaced plants will mature quicker. Increase the sowing rate for an early sowing or a site with good growing conditions. However, increasing the yield can have a detrimental effect on starch levels and pose a risk of lodging.
Can maize be used as a break crop in the rotation?
Yes, maize can act as a useful crop in a rotation, opening up more options for weed control in arable situations. The nutrients applied to the maize crop can help get a winter wheat crop away quicker.
What is the optimum drilling depth?
Drilling depth should be 5-10cm.
Achieving consistency with depth ensures that the crop comes up uniformly. Seed bed conditions should also be considered, and moisture present in the soil.
When should maize be harvested?
To achieve the best nutritional results maize should be harvested at the optimum dry matter (DM) content of 30-33%. To determine whether the crop is at the correct stage for harvesting, a visual assessment of the ‘Milk Line’ can be made.
The ‘Milk Line’ distinguishes between the hard, yellow starch part of the grain and the soft, white, (milky) starch part. As the grain matures, the milk line descends towards the centre of the cob and the proportion of hard, yellow starch increases. To achieve 30-33% DM maize silage, it is recommended to harvest when the milk line is halfway down the grain.
If the crop is harvested when the milk line is only ¼ of the way down, estimated silage DM will be 28-30%. Harvesting with a milk line ¾ of the way down will produce a DM silage of over 35%.
What are the fertiliser requirements for maize?
Taken direct from the RB209:
What are key herbicides used in a maize crop?
As maize is not a competitive crop in its early establishment phase, a pre emergence herbicide of pendimethalin is very important to keep the competitive broad leaf weeds under control. We also have very good post emergence options on both grass and broad leaf weeds, timing will vary according to weed flushes and growth conditions. Weed control between 3-5 true leaves is usually the optimum, sometimes earlier if a pre emergence herbicide has not been used. Only when the maize crop reaches 8 true levels, does it become competitive, shading out any later germinating weeds.
What are the key growth stages of maize?
The most important stage for a successful maize crop is establishment. From germination to 8 true leaves is the vital stage to ensure you have a healthy, nutrient dense maize crop at harvest. Crop nutrition at or before planting is vital to get the seeds established and growing away. As maize is a lazy rooter, down the sprout nutrients will ensure the crop gets it demand for nitrogen and phosphate from the get-go. Other elements such as calcium, magnesium and sulphur all help to set up the rooting flatform for the successful establishment.
Once crops are at the 8 leave stage, they should be very competitive against weeds, have the root system to find the applied nutrients and the yield contributing leaves to create and high yielding, nutrient dense crop.